Star Charting Apps for iPhone and iPod Touch

Starmap ProVersion 1.1

Starmap Pro is by far the most powerful of the star-charting apps, with a huge
database of 2.5 million stars and 13,200 deep-sky objects. Though intended for
serious observers using telescopes, it also has some nice features for beginners
and will appeal to many armchair astronomers.

For an app with so many features, Starmap Pro is rather spare in the
constellation department, with simple stick figures and no artist's pictures.
It will show constellation boundaries, but only when you select a constellation
by tapping on it. Notice the nice star colors.

Starmap Pro has seven different toolbars, which you can view
all at once by tapping the More button. So the tool you want is usually two taps
away.

In Starmap Pro the maximum field is 90°. You can set the horizon
to be opaque, or hide it completely, or turn on the grid and/or cardinal
directions to mark it as shown here. You can also turn the ecliptic (the dashed
line) on or off.

Zooming in reveals the enormous power of Starmap Pro, as more and
more stars appear. You can resolve dozens of open clusters besides the Pleiades,
and be amazed by the dense star fields of the Milky Way. There's sometimes a
slight, understandable delay while zooming, as the app loads more data.

The minimum field of view is about 5 arc-minutes (0.08°), much
smaller than the three-degree field shown here. Note the handy (optional) field-of-view
readout, which gives a measurement across the diagonal of the screen.

You can tap on any of the brighter stars (8900 of them) to get
a popup showing magnitude, spectral class, and coordinates. For many stars the
distance is also shown. Some of the dimmer stars are identified merely as "star",
with no catalog number. Tapping the popup then takes you to a detailed
emphemeris page with rise, set, and transit times, plus a graphic showing
when the star is visible and a second graphic (see example below) showing altitude
vs. time. (There seems to be a minor bug, however, in the time computations: notice
that the transit time displayed here is several minutes later than the midpoint between
the rise and set times.)

Starmap Pro draws planets as actual images.
The popup and emphemeris pages work the same for planets as stars,
but for each planet you also get a small image, and for four of the planets
(Mars, Jupiter, Saturn, Uranus) the emphemeris pages show current moon locations.
Starmap Pro also has the ability to zoom in directly
on planets (as well as the moon). As you zoom, the planet's image first shrinks to its actual size, then
grows as you zoom further. For Jupiter and Saturn you can also view the current
moon locations this way. Notice that Saturn's rings are shown in their
current orientation.

Starmap Pro includes the complete NGC and IC catalogs of deep-sky
objects--more than 13,200 in total. The fainter ones appear as you zoom in, just as
for stars. You can switch each class of objects on or
off in the Settings, but you can't set a magnitude limit for DSOs.

Besides the various symbols for deep-sky objects, Starmap Pro will
show circles representing their approximate sizes (when this feature is enabled).
You can tap on a DSO to identify it and get ephemeris information, just as for a
star or planet. Starmap Pro will also show a small photo in the popup for each
of the Messier objects (and for planets).

There are two ways to change the time in Starmap Pro. The Date & Time button lets
you dial up a date and time on a separate screen. Alternatively, you can tap the
Time slider button and then drag your finger horizontally to adjust the time, and/or
vertically to adjust the date. But this method is convenient only for fairly small
changes, and you can't otherwise animate the passage of time.

Unfortunately, there is a bug in the way Starmap Pro handles
daylight savings time. For example, when DST is currently in
effect at your location, but you set the app to view the sky during a season when
DST should not be in effect, all the times are an hour off--and turning off
the DST switch throws the times off by an additional hour!

In Starmap Pro there are two ways to search. One is to tap a
toolbar button for the desired object class (Planets, Constellations, Stars,
Galaxies, Clusters, Nebulae, or Meteors), then scroll through a list to select
the desired object. For the three categories of deep-sky objects, you first get
a list of constellations to scroll through, then a list of objects in the selected
constellation, sorted by brightness. Either way, tapping the blue arrow button
takes you to the ephemeris
page for the object, while tapping the object name takes you straight back to the
sky chart with the object highlighted. You can also set it to guide you to the
object with an arrow, starting from wherever the chart was previously pointed.

Alternatively, there's a Catalogue button that lets you type in
the name (or partial name) of an object, then select from a list of objects
that match the entered name. This search feature is a bit slow,
presumably due to the size of the catalog being searched.

One of Starmap Pro's most useful toolbar
buttons is the brightness control, shown at left, which has separate sliders for the
sky background (black to light blue) and star image size.

Separate toolbar buttons let you set the location and time.
The Settings button handles almost everything else, taking you first to a menu
listing Navigation, Solar System, Stars, Deep sky, and Colors. A separate page
gives you access to each of these groups of settings. The color settings are a good
idea but rather poorly implemented, with an incomplete range of hues and no control
over saturation. It does give you separate control over the colors of most of the
lines, text, and symbols that appear on the chart, but doesn't let you assign
separate colors to different categories of deep-sky objects.

Summary

Strengths:

Huge database of 2.5 million stars and 13,200 deep-sky objects

Unique tools for telescopic observers

Gives the user almost complete control over what is and isn't displayed

Easily accessible brightness controls

Extensive help screens

Suggested Improvements:

Allow zooming out to show the whole sky at once.

Add time animation.

Simplify the toolbars to reduce the number of different buttons.

Add the ability to draw constellation boundaries.

Fix the bugs pertaining to daylight savings time and rise/set/transit times.

Ease of Use Rating:
The sheer number of features makes this app necessarily complex. The user interface
is straightforward but uninspired. The developer has
made a real effort to assist beginners through help screens and some other nice
features.

Information Content Rating:
The enormous databases and detailed ephemeris information put this app in a class
by itself.

Fun Factor Rating:
The graphics are attractive and reasonably responsive. The vast content can
entertain you for hours. But the lack of time animation and the
mediocre user interface might keep you from having too much fun.